Electrodeposition of nickel



Patented July 7, 1953 UNITED STATES PATIENT-ffOF'FlCE. v H 2,644,789 T.fl Y a i ELECTRODEPOSITION F NICKEL I WilburJ. Shenk, Jr., ShakerHeights, Ohio, as-

signor 'to The' Harshaw Chemical Company, "Cleveland, Ohio, atcorporation of O hio N0 Drawing. Application Augusta, 195 i, I

I -"serial No. 240,049

1 7 Claims. (Cl. 204-49) This invention relates to electrodeposition ofThe substances of the first addition agent class metals, and morespecifically to a process of, the bis-pyridinium. compounds, are solubleand solutions for use' in a process of, electrothe solution to theextent of at least about .005 depositing nickel, characterized in thatthe regram per liter '(for example,in ajsolution con sulting nickelelectrodep'osit is brightas it comes taining 240 grams, per literNiSO4-6H2O, 37.5 from the plating solution. More particularly, grams perliter of NiC12-6H2O, and 37.5 grams the present invention has to do withthe discovery per liter of HaBOa, remainder water) and should ofcooperating brightening addition agents suitbe understood to include theunsubstituted pyable for use in an aqueous acid nickel platingridiniu'm'group and also substituted pyridinium solution. groups such asthose having alkyl substituents I have now discovered that excellentbright, or substituents coalesced into a ring structure ductile, andsmooth deposits of nickel can be soas to give, for example,isoquinolinium groups. produced over a wide cathode current densityAddition agents of the first mentioned class range by electrolyzing anaqueous, acid solution are characterized by the presence of two spacedof a nickel electrolyte of the class consisting of groups of the form,

nickel sulfate, nickel chloride, and mixtures of nickel sulfate withnickel chloride, if such solu- @J; tion also contains an effectiveamount of each of two cooperatingaddition '-agents, -one of such vaddition agents being a bis-pyridinium compound I I soluble in saidsolution to the extent of at least 1 1 .005 gram per' liter andcharacterized in that the the Open valences being satisfied by varioussubtwo pyridinium groups are connected through stituentssuch as hydrogenor alkyl (methyl, ethyl, a carbon chain or a carbon and oxygen chain,propyl) =chlorine,-- bromine, etc. The general and the other of saidaddition agents being a structure may be indicated as follows;

cyclic, organic sulfur compound soluble in the i I I acid nickelsolution to' the extent" of f at least l 0.2 gm. per liter,and-selected'frointhe group consisting of organic compounds containingthe I 2 group v g 3U I. 1 l

g g v s Where ZYmay indicate a connecting chain which g p v may be achain of from 1 to 5 methylene groups I or aplurality of chains of fromlto5 methylene wherem the carbon atom is nuclear carbon, and groupsconnected through oxygen or phenylene in which compounds each of theremaining nuor a chain of from 1- to 3 phenylene groups any clear carbonatoms carries a group of the-class f the replaceable hydrogens of whichmay be gn of hydrogen, methyl, ethyl, chlorine, substituted. The aboveindicated cyclic nitrogen bromin CH0, and Phenyl The filfst memlonedgroup, when all the'free valences are satisfied by agent may be referredto as the b1spyr1dinium 40 hydrogen, is referred to as a pyridiniumgroup brightener and should be maintained in-the plat- A pl mit of b t tt may form a ring m ing solution in concentration from 0.005 to 0.05 'tfor example, isoquinolinium which has the gram per liter, preferablyfrom 0.001 to 0005' "following Structure; gram per liter, while thesecond mentioned addition agent, which I.prefer to. call fa carrier. orJ L regulator, should be maintained in the solution in a concentrationof from 0.2 to 15.0 gm. per 0 liter, preferably from 1 to 7 gm. perliter. 1 K L Since the two above-mentioned classes of ad- I 1 3 Y 1dition agents are intrinsicallyand-functionally 1 1 distinct, theywillbe separately described and identified One or more of the hydrogens maybe substituted 3 4 by alkyl giving an alkyl pyridinium group. In b.N,N-(oxydiethylene)-bis-pyridinium general the unsubstituted pyridiniumgroup or perchlorate the unsubstituted isoquinolinium group is preferredas being simpler, but the substituted groups can be used. The connectinggroup or 5 HC fi CH 2010- chain is made up of methylene and/ orphenylene and/or oxygen. It may take the form of a single g'g g'fimethylene group, a single phenylene group, or a more complexarrangement. If the pyridinium ig zfigg bis pyndlmum group, theisoquinolinium group, and "substituted v. pyridinium and isoquinoliniumgroups are lndi- 2g 6 cated by P and P, the desirable compounds may tsuch forms HO %N-CH:-OCH:N\ CH+ 2C1- (c -o o-c PCH2-P' F H H HPCH2O-CH2--P d. N,N-'(6xydifiiethy1ene)-bis-isoquinolinium PCH2C6H4CH2Pv chloride I g:ggggfigi being an integer from 1-5) The structure iswritten like (c) substituting P [CHC6H5] CH isoqumolmium groups for thepyridimum groups. PCH2CH2CH2CHPP' e. N,N-(oxydimethylene)-bis-(2-methyl-5- These are merely examples, and numerous ethyl)pyndmium chlonde other arrangements'as possible. V CH C To classifythese addition agent's into 'sub- H H classes, most of them fall intothree groups, hav- I general formulae as follows: no N-CHfib-CHFN CH201- Group 1;-P'[CRR"]n O([CRR'lw-Ohwcmgq m p' where P and P 'have'themeaning I H H indicated above, Rand R"m'ay be, independent1y, mm

hydrogen, alkyl (methyl,'ethyl,propyl), phenyl, H v Y etc., 11, n and11/ may be'integers from 1 to 5, f. N,N-[oxydi-"(trinrethylehwlhis-pyridi'nium and 1L" may be an integer from 0 to 3. chloride H H 'H Ho -o 'c o no iI-cHHCiIECEFO CHFCHFCnfii f 1111+ 201- Group 2.P-[CRR']nPwhere P and P g. N',N'-(oxyethylenemethylene)-bis-pyridinium have themeaning indicated above, R and R chloride may be, independentlmhydrogen,alkyl (methyl, H H (H H ethyl, propyl), phenyl, etc., and n is aninteger O=C /c= 0 1 U r. r HQ g e a H Group 3 P -[QRR/]n-(C6H4-[CRR']M)nf' g HP K 2 Hm P where P andP' have the meaning indicated37% 75 above, R and R may be, independently, hydror I H V gen, alkyl(methyl ethyl, propyl), phenyl, etc., .N'- oxy hyl i oquinoliniumchloride 11 is an integer from 1 to 3, n is arr integer from hylene)pyridinium chloride 0 to 3, and n is an integer from 1 to 3.

Some specific examples of the foregoing three &4; 2 5 groups are asfollows: E i

o-o N-cH,-o-orr,-or1,-N /CH 201- Group 1.-AZkylene-ether*type li'nka'geHC c-g c c Y V V. H H a. N,N-(oxydiethylene) bis-isoqulnoliniuin 31%chloride H 11 II E H H 0-0 CH,-CHr 0"'OBg'0H{ I I ,C---C HC\ o'- %-o /CH201- o=o c=o H H H H i. -N,N'-('dioxytrieth'y1ene) -bi's'-1pyr-idiniumchloride H H as v a HO %NCHrOHrOCHfiCHv-O=CHFCKF-N; on 201- an HR a. N,N (oxydiet hylene) -bis-3-methyliso- 1 quinolinium chloride k. N,N-(oxymethy1ene) -pyridinium chloride- (ethy1ene)isoquino1iniumchloride I. N,N'-cyc1ohexene-bis-byridinium bromide I d.N,N-(pxy1y1ene)-bis-isoquii101inium bromide:

ond addition agent class are soluble in the plating 7 solution (forexample, in a solution consisting of 240 grams of NiSO4'6H2O, 37.5 gramsNiClz- SHaO; 37.5 grams of H3303, and water to make a liter), to theextent of at least 0.2 gram per liter. These include such materials asbenzene, naphthalene and thiophene sulfonic acids and salts thereof, andhalogen, methyl, ethyl, CH0, and phenyl substitution products of theforegoin such as, for example:

CARRIERS OR REGULATORS- Benzene mono-sulfonic acid (CsHsSOaH) Benzenedisulfonic acids (CeH4(SO3H)2) Monochlorbenzene monosulfonic acids 4.Dichlorobenzene disulfonic acids (C12CsH2(SO3H) 2) 5.2,5-dibromobenzenesulfonic acid (BrzCeHaSOaH) 6. Toluenesulfonic acids(CH3C6H4SO3H) 7. Benzaldehydesulfonic acids (C6H4(CHO)SO3H) 8.Diphenylsulfonic acids (CsH5C6H4SO3H) 9. Thiophenesulfonic acids (ClHIiS'SOZlH) Diphenyl sulfone sulfonic acids (CsHsSOzCsI-RSOsI-I)Naphthalene disulfonic acids Naphthalene monosulfonic acidsChloronaphthalene disulfonic acids Dibenzenesulfonamide [(CsHsSOz) zNH]Dichloro dibenzenesulfonamides (C12C6H3SO2NHSO2C6H5) N-ethane sulfonylbenzene sulfonamide (CsHsSOzNHSOzCzHs) Potassium, sodium, nickel andcobalt salts of the foregoing Benzene monosulfonamide (C6H4SO2NH2)saccharine, sodium salt (C'sI-LiSOaCONNa) or anhydride (CsH4SOzCONH)Benzenesulfonyl chloride (CsHsSOzCl) Chlorobenzenesulfonamides('ClC6H4S'OzNH2) Xylenesulfonamides ((CHz) zCsH3SO2NH2)Toluenesulfonamides (CH3CsH4SO2NI-I2) Sulfonated naphthalene. (Mixturesof naphthalene. sulfonic acids, produced by (treating naphthalene witholeum, preferably two parts of 20% oleum on one part of naphthalene at160 C. for two hours.)

From these examples it becomes clear that numerous single ring compoundscontaining the effective group can be used, whether aromatic, such asthe benzene sulfonic acids, or heterocyclic with aromaticcharacteristics, such as thiophene sulfonic acid. Various substituentson the ring structure are exemplified.

It is to be understood that all statements made herein concerning thecapabilities of the addition agents presuppose the use of one or amixture of two or more from each class, i. e., one or a mixture from thebis-pyridinium class and one or a mixture from the class of aromaticsulfur compounds containing the comgroup. The carrying agents produce adegree of brightness without any brightener, but not enough to yieldfull brightness-alone. I prefer the use of the more common and readilyavailable compounds, and prefer to employ in each addition agent classonly compounds devoid of the group which characterizes ,the otheraddition agent class.

The constituents of the bath according to the preferred practice of theinvention are (1) water, (2) nickel sulfate, nickel chloride or nickelsulfate with nickelchloride, (3) an aromatic sulfonyl compound such asan aromatic sulfonic acid or a nickel, alkali metal, or cobalt saltthereof, an aromatic sulfonamide, or sulfimide, or a mixture of aplurality thereof, (4) a wetting agent (optional) ar 1d (5) abis-pyridinium compound or a mixture'of 'bis-pyridinium compounds. Anadditional ingredient of the solution which is desirable is a. bufferingagent such as boric acid,

formic acid, ammonium sulfate, or the like.

It will benoted that in respect to major constituents, the solutions aresimilar to the wellknown ..all sulfate, all chloride, and"sulfatechloride orWatts type acid nickel plating solutions. It will benoted also that as to the aromatic sulfonyl type of addition agent orcarrier, as it is often called, the group of suitable-materials are ofthe type which is represented by well-known carriers in the brightnickel plating industry. The essential novel feature of the presentinvention is the use in such solutions containing the aromatic sulfonylgroup of a small amount of a bis-pyridinium compound or a mixture ofbispyridinium compounds.

The "preferred basic solutions in connection with whichmy invention isrealized are as follows:

:ALL SULFATE to 400 g., preferably H 200to300g. Boric' acid 0 to g.,preferably 10 0 Wetting agent (e. g., sodium 0 to 0.5 g., preferably0.05

lauryl sulfate). to 0.2 g. H O to make 1000 cc.

ALL CHLORIDE NiCl -6H O 50 to 250 g., preferably 100 to 200 g. BOIlCacid 0 to g., preferably 10 o g. Wetting agent (e; g, sodium 0 to 0.5g., preferably 0.05

lauryl sulfate). 0 0.2 g.

H2O to make 1000 cc.

SULFATECHLORIDE (WATTS TYPE) nisogm'go 100 to 400 g., preferably 200 to300 g. N1Cl -6H O 10tto4g0 g., preferably 25 0 ..Bor1c acid 0 E0 g.,preferably 15 1 l 0 g. \Vettlngugenb-(eyg sodium 0 to 0.5 g., preferablylauryl sulfate). 0.025 to 0.2 g.

H2O to make 1000 cc.

To each of theforegoing basic solutions I add .a suitable quantity ofeach,--or a mixture of W or ncre of "each, of the two co-operatingaddition agents; One of said addition agents or mixtures is one of thearomatic sulfonyl type, and the other is of the bis-pyridinium typedescribed :above, The I solution should, for best results,

contain an anti-pit agent,'although the deposits may be suitable forsomepurposes without eliminating the pitting, and under some conditions thedeposits may' not be objectionably pitted even in the absence of anaddition agent for control of pitting; Sodium lauryl sulfate or otheralkyl sulfate having 8 to 18 carbon atoms may be used as an anti-pitagent, although, as stated, its use is not essential, and other wettingagents or mixtures of wetting agents may be used for control of pitting.

' The specific examples in the following table will serve to illustratethe invention, values therein being grams per liter except as otherwiseindicated, the balance being water.

Benzene monosulionie acid. saccharine (Sodium salt)N,N-(dioxytriethylene)-bis-pyridinium chlorideN,N-(oxydiethylene)-bis-isoquinolinium chloride N,Ngmethylene-bis-pyridinium bromi e Para xylylenc-bis-pyridinium bromideN,N-m ethyl en e-b is-isoquinolinium bromide om eN,N-o-xylylene-bis-pyridiniurn bromide Temperature in DegreesFahrenheit. Cathode Current Density in Amperes Hper Square Foot 120 D ISulfonated naphthalene is the product of reacting {parts of 20% oleum on1 part of naphthalene at 160 C. for 2 hours, neutralizing the resultingmixture with nickel carbonate and diluting to to Be. 5 cc. of thisproduct is roughly equal to 1 gram of nickel naphthalene mixedsulionate.

Having thus described my invention, what I claim is: r

1. A method of electrodepositing nickel in the form of a deposit whichis bright as taken from the plating solution without further treatmentand which comprises electrolyzing an aqueous, acid solution of a nickelelectrolyte of the class consisting of nickel sulfate, nickel chloride,and mixtures of nickel sulfate with nickel chloride, said solution alsocontaining cooperating addition agents capable of imparting brightnessto the deposit, one of said addition agents being a compound comprisingtwo heterocyclic radicals, each containing a nitrogen atom in ati-membered ring, and said radicals being connected to each otherthrough said nitrogen atoms by means of a carbon-containing group, saidgroupv being selected from groups of the class consisting of carbonchains having from 1 to 12 carbon atoms and chains made up of carbon andoxygenand containing not more than a total of 12 connecting atomsbetween said nitrogen atoms, and the other of said addition agents beingan aromatic compound containing the r group, and being soluble in saidsolution-toflthe extent of at least 0.2 gram per liter, the carbon atomis said o =t l group being nuclear carbon, said first mentioned additionagent being present in concentration from 0.005 to 0.01 gram perrliter,and saidsec- 0nd mentioned addition agent being present in concentrationfrom 0,2 to 15 grams per liter.

2. A method of electrodepositing nickel in the form of a deposit whichis'bright as taken from the plating solution without further treatmentand which comprises electrolyzing an aqueous, acid solution of a nickelelectrolyte of the class consisting of nickel sulfate, nickel chloride,and

mixtures of nickel sulfatevwith nickel chloride,

compound of the formula,- Y

said solution also containing cooperatingaddition agents. capableofimparting brightness. to the deposit, one of said addition agents beinga compound of the formula,

I eas where Pand P are radicals of'the' iormula and the other of saidaddition agents being an aromatic compound containing the I I =C group,and being soluble in said solutionto the extent of at least 0.2 gram perliter, the carbon atom in said form of a deposit which is'bright astaken from the plating solution without further treatment and whichcomprises electrolyzing an aqueous, acid solution of a nickelelectrolyte of the class consisting of nickel sulfate, nickel chloride,and

.m'ixtures of nickelsulfate. with nickelchloride,

said solution also containing cooperating addition agents. capable ofimparting brightness to the deposit, one of said addition agents being awhere Pad P: are radicals of the formula and the other of said additionagents being an aromatic compound containing the a e deposit, oneefsaidaddition agents being a compound of: the class consisting ofgroup, and being soluble in said solution to the extent of at least 0.2gram per liter, the carbon atom in said group being nuclear carbon, saidfirst mentioned addition agent being present in concentration from 0.005to 0.01 gram per liter, and said second mentioned addition agent beingpresent in concentration from 0.2 to 15 grams per liter.

4. A method of electrodepositing nickel in the the form of a depositwhich is bright as taken from the plating solution without furthertreatment and which comprises electrolyzing an aqueous, acid solution ofa nickel electrolyte of the class consisting of nickel sulfate, nickelchloride, and mixtures of nickel sulfate with nickel chloride, saidsolution also containing cooperating addition agents capable ofimparting brightness to the deposit, one of said addition agents being acompound of the formula,

where P and P are radicals of the formula and the other of saidadditionagents being an aromatic compound containing the group, andbeing soluble in said solution to the.

extent of at least 0.2 gram per liter, the carbon atom in said O LLgroup being nuclear carbon, said first mentioned addition agent beingpresent in concentration from 0.005 to 0.01 gram per liter, and saidsecond mentioned addition agent being present in concentration from 0.2to 15 grams per liter.

5. A method of electrodepositing nickel in the form of a deposit whichis bright as taken from the plating solution without further treatmentand which comprises electrolyzing an aqueo u s,-

acid solution of a nickel electrolyte of the class consisting of nickelsulfate, nickel chloride, and mixtures of nickel sulfate with nickelchloride, said solution also containing cooperating addition agentscapable of imparting brightness to the N,N' (oxydiethylene)-bis-isoquinolinium salts, N,N- (oxydiethylene) -bis-pyridinium salts,

N,N-(oxydimethylene) -bis.-pyridinium salts,

N,N'- (oxydimethylene) -bis-isoquinolinium salts,

N,N' (oxydimethylene) bis (2 methyl 5 ethyl) pyridinium salts,

N,N- [oxydi (trimethylene) l -bis-pyridinium salts,

N,N (oxyethylene methylene) bis pyridinium salts,

N,N(oxymethylene) isoquinolinium (ethylene) pyridinium salts,

N,N (dioxytriethylene) -bis-pyridinium salts,

NJN (oxydiethylene) --bis 3 methylisoquinolinium salts,

N,N (oxymethylene) isoquinolinium salts,

N,N-ethylene-bis-quinolinium salts,

pyridinium(ethylene) N,N-methylene-bis-pyr-idiniumsalts,

N,N'-ethylene-biS-pyridinium salts,

L N,N' -methylene-bis-is oquinolinium salts,

. N,N -methylene-bis.-(a-picolinium) salts, -N,EN--cyclohexene-bis-pyridinium salts,

N,N-styrene-bis-pyridinium salts,

N,N methylene bis (2 methyl 5 ethyl pyridinium salts,

N,N'-(o-xylylene) -bis-pyridinium salts,

N,N (p-xylylene) ems-pyridinium salts,

N,N- (p-xylylene) -bis- (a-picolinium) salts,

N,N e (p-xylylene) -bis-isoquinolinium salts,

and the other of said addition agents beng a cyclic organic compound ofthe class consisting of Chlorobenzenesulfonamides, Xylenesulfonamides,

Toluenesulfonamides, Sulfonated naphthalene,

said first mentionedaddition agent being present in concentration from0.005 to 0.01 gram per liter, and said second mentioned addition agentbeing present in concentration from 0.2'to 15 grams per liter.

6. A method of electrodepositing nickel in the form of a depositwhich'is bright as taken from the plating solution without furthertreatment and which comprises eleotrolyzing an aqueous,

'acid solution of a nickel electrolytev of the class consisting ofnickel sulfate;'nickel chloride, and

mixtures of nickel sulfate with nickel chloride,

said solution also containing cooperating addition agents capable'ofimparting brightness to the deposit, one-of saidaddition agents beingoxydi- 13 I ethylene-bis-isoquinolinium chloride, and the other of saidaddition agents being sulfonated naphthalene, said first mentionedaddition agent being present in concentration from 0.005 to 0.01 gramper liter, and said second mentioned addition agent being present inconcentration from 0.2 to 15 grams per liter.

7. The invention as defined in claim 6 further characterized in thatthere is included as a third addition agent, 2,5-dich10rodibenzenesulfonamide in quantity such that the combined concen- 14trations of the sulfonated naphthalene and 2,5-dichlorotdibenzenesulfonamide are within the range from,0.2 to 15 gramsper liter.

WTLBUR' J. SHENK, JR.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 10 2,513,280 Brown July 4, 1950 2,550.44!) Brown Apr. 24, 1951

1. A METHOD FOR ELECTRODEPOSITING NICKEL IN THE FORM OF A DEPOSIT WHICH IS BRIGHT AS TAKEN FROM THE PLATING SOLUTION WITHOUT FURTHER TREATMENT AND WHICH COMPRISES ELECTROLYZING AN AQUEOUS, ACID SOLUTION OF A NICKEL ELECTROLYTE OF THE CLASS CONSISTING OF NICKEL SULFATE, NICKEL CHLORIDE, AND MIXTURES OF NICKEL SULFATE WITH NICKEL CHLORIDE SAID SOLUTION ALSO CONTAINING COOPERATING ADDITION AGENTS CAPABLE OF IMPARTING BRIGHTNESS TO THE DEPOSIT, ONE OF SAID ADDITION AGENTS BEING A COMPOUND COMPRISING TWO HETEROCYCLIC RADICALS, EACH CONTAINING A NITROGEN ATOM IN A 6-MEMBERED RING, AND SAID RADICALS BEING CONNECTED TO EACH OTHER THROUGH SAID NITROGEN ATOMS BY MEANS OF A CARBON-CONTAINING GROUP, SAID GROUP BEING SELECTED FROM GROUPS OF THE CLASS CONSISTING OF CARBON CHAINS HAVING FROM 1 TO 12 CARBON ATOMS AND CHAINS MADE UP OF CARBON AND OXYGEN AND CONTAINING NOT MORE THAN A TOTAL OF 12 CONNECTING ATOMS BETWEEN SAID NITROGEN ATOMS, AND THE OTHER OF SAID ADDITION AGENTS BEING AN AROMATIC COMPOUND CONTAINING THE 